1. Technical Field
The present invention relates generally to manufacturing control systems, and more particularly, to integration of a factory level advanced process control (APC) system and a local tool level APC system.
2. Related Art
Manufacturers, especially semiconductor fabricators, who implement advanced process control (APC) systems, generally do so at the factory level. APC systems take measurements of particular structures before and after a processing step and provide corrections to recipes for feeding forward and/or feeding back to tools to achieve a better product. Typically, factory level APC systems are implemented such that individual tools are controlled by the factory level APC system. Presently, however, tool vendors are beginning to implement embedded APC systems in tools. For example, FIG. 1 shows a typical semiconductor fabricator environment 10 including a number of tools 12, a manufacturing execution system (MES) 14 that controls all product movements through environment 10, i.e., it schedules product movements, a factory level APC (FL-APC) system 16, and an equipment interface (EI) 18 that interfaces between MES 14 and different tools. Although not shown, middleware may be present for communication between MES 14, FL-APC system 16 and EI 18. Each tool 12 includes process equipment 20 particular to its function, e.g., an etching chamber, gas source, appropriate electronics, etc. for an etching tool. Metrology instruments may be provided as an integrated metrology (IM) system 22 and/or external metrology systems 24 and 26.
Presently, tool manufacturers are beginning to implement advanced process control systems on their tools. Accordingly, each tool 12 may now include a tool level APC (TL-APC) system 30. Although new tool level APC systems hold promise for increased efficiency, they also present a challenge in that no effective and standard method exists to coordinate and manage the process control functions between the factory level APC system and the tool level APC system. Accordingly, each tool with a new tool level APC system represents a set of customization challenges relative to integration with the factory level APC system. In addition, the variety of scenarios that must be addressed is based on which of the following is desired: FL-APC and/or TL-APC control, external and/or integrated metrology, lot-to-lot and/or wafer-to-wafer evaluation. As a result, the customization challenges are immense.
In view of the foregoing, there is a need in the art for a solution for integrating factory level and tool level APC systems.